简易的文档编辑程序，可以打开、编辑记事本文档，增加了更换颜色功能。在状态栏里可以显示字符数量，字符属性。初学者可以通过本代码学习C#-Easy document editing program, you can open, edit Notepad document, and change color. The number of characters, character attributes can be displayed in the status bar. Beginners can